摘要 |
A pressure relieved piston rod seal for piston-cylinder having tandem seals around the piston rod which are subject to failure when the pressure between the seals is greater than the pressure in the cylinder chamber. The piston rod seal of this invention solves this problem by providing a unidirectional seal between the end or low pressure rod seal and the cylinder chamber which relieves the pressure between the seals while sealing the chamber. The unidirectional seal includes a fluid passage which permits fluid flow into the cylinder chamber when the pressure between the seals is greater than the pressure in the cylinder chamber and seals the cylinder bore when the pressure in the chamber is greater than the pressure between the seals.
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